North Carolina Standard Course of Study
NC.1.OA. Operations and Algebraic Thinking
Understand and apply the properties of operations.
NC.1.OA.3. Apply the commutative and associative properties as strategies for solving addition problems.
NC.1.OA.4. Solve an unknown-addend problem, within 20, by using addition strategies and/or changing it to a subtraction problem.
Add and subtract within 20.
NC.1.OA.9. Demonstrate fluency with addition and subtraction within 10.
NC.1.OA.6. Add and subtract, within 20, using strategies such as:
NC.1.OA.6.a. Counting on
NC.1.NBT. Number and Operations in Base Ten
Use place value understanding and properties of operations.
NC.1.NBT.6. Subtract multiples of 10 in the range 10-90 from multiples of 10 in the range 10-90, explaining the reasoning, using:
NC.1.NBT.6.d. Properties of operations